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Tropical birds are usually placed in the 'slow' end of the life-history continuum, and much of their physiology matches the trade-off between lifespan and reproduction. For example, they demonstrate lower wholeanimal basal metabolic rates (BMR) and peak metabolic rates (PMR) compared with temperate birds, and at the cell level, tropical birds also have lower rates of oxygen consumption. Oxidative stress, a by-product of aerobic respiration, has yet to be fully elucidated to be linked to life-history theory. However, previous work suggests that tropical birds may have superior antioxidant capacity to birds that live in temperate areas. In the current study, we used muscle tissue from 35 species of tropical birds to measure total antioxidant capacity (hydroxyl scavenging capacity and peroxyl scavenging capacity), the activity of antioxidant enzyme catalase (CAT), superoxide dismulase (SOD) and glutathione peroxidase (GPx), and lipid damage (LPO). We correlated these measurements to body mass and found a significantly negative correlation between body mass and LPO and a marginally significant negative correlation with hydroxyl scavenging capacity. Interestingly, we also correlated our measurements to literature reported BMR measurements from 22 species included in our study and found no correlations. A negative correlation between body mass and LPO damage may be due to cellular muscle structure and mitochondrial content and structure within the muscle. Received 6 October 2021. Accepted 24 May 2022. Key words: basal metabolism, life-history, muscle, oxidative stress, tropical birds. Las aves tropicales generatmente se ubican en el extreme- 'lento' del eontinuo dc la historia de vida. y gran parte dc su fisiologia coincide con el equilibrio cntrc la vida util y la rcproduccion. Por ejemplo, las avcs dcmucstran tasas metabolicas basalcs (BMR) y tasas metabolicas maximas (PMR) de animal complcto mas bajas en comparacion con las avcs dc clima templado y. a nivel cclular. las aves tropicalcs tambicn tienen tasas mas bajas dc consume- dc oxtgeno. El estres oxidativo, tin subproducto dc la respiration aerobica. atin no sc ba dilucidado por complcto para vincularlo a la tcoria dc la historia dc vida. Sin embargo, trabajos previos stigicrcn que las aves tropicalcs ptieden tcner una capacidad antioxidamc superior a las aves que viven en areas templadas. En cste estudio. utilizamos tcjido muscular dc 35 especies dc avcs tropicalcs para medir su capacidad antioxidamc total (capacidad de captacion dc hidroxilo y capacidad dc captacion dc peroxilo), la actividad de la enzima anlioxidante catalasa (CAT), la superoxido dismutasa (SOD), la glutation peroxidasa (GPx) y el dano de It'pidos (LPO). Correlaeionamos cstas medicioncs con la masa corporal y encontramos una correlation signiticativamente negativa entre la masa corporal y la LPO, y una corrclacion ncgativa marginalmente significativa con la capacidad de captacion de hidroxilo. C'uriosamente. tambien correlaeionamos nuestras mediciones con mediciones de BMR encontradas en la litcrattira para 22 especies incluidas en nucstro estudio y no encontramos correlacioncs. Una corrclacion ncgativa cntre la masa corporal y el dano por LPO pucde debcrsc a la cstructura muscular cclular. y al contcnido y cstructura mitocondrial dentro del musculo. Palabras clave: avcs tropicalcs. estres oxidativo. historia dc vida, metabolismo basal, musculo,, Variation in life-history events, such as growth rate, maintenance, body size, reproductive output, and timing reflect the crux of life-history theory, which states that a differential allocation of resources may [...]

Research has been conducted on the aryl halides. Results demonstrate that the amination of these compounds carried out in the presence of air-stable alkali metal hydroxide bases and a palladium catalyst has produced arylamines.

The present studies were undertaken to determine the direct effects of nitric oxide (NO) released from an exogenous donor, S-nitroso-N-acetyl pencillamine (SNAP) on [Cl.sup.-]/O[H.sup.-] exchange activity in human Caco-2 cells. Our results demonstrate that NO inhibits [Cl.sup.-]/O[H.sup.-] exchange activity in Caco-2 cells via cGMP-dependent protein kinases G (PKG) and C (PKC) signal-transduction pathways. Our data in support of this conclusion can be outlined as follows: 1) incubation of Caco-2 cells with SNAP (500 [micro]M) for 30 min resulted in ~50% inhibition of DIDS-sensitive [sup.36]Cl uptake; 2) soluble guanylate cyclase inhibitors Ly-83583 and (1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one significantly blocked the inhibition of [Cl.sup.-]/O[H.sup.-] exchange activity by SNAP; 3) addition of 8-bromo-cGMP (8-BrcGMP) mimicked the effects of SNAP; 4) specific PKG inhibitor KT-5823 significantly inhibited the decrease in [Cl.sup.-]/O[H.sup.-] exchange activity in response to either SNAP or 8-BrcGMP; 5) [Cl.sup.-]/O[H.sup.-] exchange activity in Caco-2 cells in response to SNAP was not altered in the presence of protein kinase A (PKA) inhibitor (Rp-cAMPS), demonstrating that the PKA pathway was not involved; 6) the effect of NO on [Cl.sup.-]/O[H.sup.-]-exchange activity was mediated by PKC, because each of the two PKC inhibitors chelerythrine chloride and calphostin C blocked the SNAP-mediated inhibition of [Cl.sup.-]/O[H.sup.-]-exchange activity; 7) S[O.sup.2-.sub.4]/O[H.sup.-] exchange in Caco-2 cells was unaffected by SNAP. Our results suggest that NO-induced inhibition of [Cl.sup.-]/O[H.sup.-] exchange may play an important role in the pathophysiology of diarrhea associated with inflammatory bowel diseases. chloride absorption; human intestine; guanylate cyclase; protein kinase C regulation

Research has been conducted on delta-hydroxy esters. The results of the kinetic resolution of the delta-hydroxy ester racemic mixture obtained via lipase-catalyzed transesterification are presented.

Research has been conducted on [60]fullerene. The results of the photochemical reactions of this fullerene with aromatic ketones or aldehydes have been investigated and discussed.

Research has been conducted on the crystalline, anhydrous, microcrystalline, amorphous and aqueous thorium(IV) solutions and colloidal suspensions. The use of the X-ray absorption fine structure spectroscopy at the Th L3 edge in characterizing these solutions is described.

Research has been conducted on the layered double hydroxides with a cation position of LiAl (sub)2 which have a lot of applications including lithium aluminate phases. The calcination behavior of this group of the layered double hydroxide phases has been investigated and the results of the X-ray diffraction exploring the thermal evolution of the chloride that contains the LiAl (sub)2 layered double hydroxide compound are presented.

Research has been conducted on the iron complexes, verdohemes. The reaction of the 5-oxaporphyrin iron complexes with methoxide or hydroxide ions has been examined in investigating the verdoheme ring opening initial step and the results are reported.

Research has been conducted on the hydroxide ion. The use of the Becke's three-parameter hybrid density functional-HF method, the Lee-Yang-Parr correlation functional and the second-order Moller-Plesset theory in investigating the nucleophilic substitutions by this ion at vinylic carbons of methoxyethene is discussed.

Research has been conducted on the uranium(VI) fluoride complex. The structures of this complex has been examined via EXAFS, and the structure and bonding in the uranium(VI) fluoride and hydroxide complexes have been compared.

Research has been conducted on the nucleophilic substitution reactions which involve simple species such as nucleophile and leave group in methylsulfenyl derivatives. Results indicate that the reactions involving hydroxide and amide correspond to deprotonation and not substitution and that the substitution reactions follow the addition-elimination pathway.

The authors discuss synthesis and characterization of L-tyrosine and L-phenylalanine interrelated montmorillonite and Zn-Al layered double hydroxide. FT-IR spectroscopy and thermogravimetry were used to compare thermal behavior of different materials.

Research has been conducted on the plutonium oxide and plutonium hydroxide. The role of different chelators including trihydroxamate desferrioxamine E and B in plutonium oxide and plutonium hydroxide dissolution in neutral buffered solutions has been investigated and the results are reported.

The sequence- and structure-based predictive methods coupled with experimental validation were used to characterize the structure and function of the Escherichia coli K-12 protein YfaU, annotated as a putative 4-hydroxy-2-ketoheptane-1,7-diolate aldolase (HpcH) in the sequence databases. The findings for crystal structures revealed that the enzymes used an Asp-His intersubunit dyad to activate a metal-bound water or hydroxide for proton transfer during catalysis.